1. Field of the Invention
The present invention relates to an adjustable valve and more particularly to an adjustable valve having a valve mechanism which includes a replaceable flow nozzle and a replaceable flow cone.
2. Description of the Prior Art
U.S. Pat. No. 2,684,688, entitled Automatic Valve and System, issued to Homer G. Thornhill on Jul. 27, 1954, teaches an adjustable valve which includes a T-shaped fitting, a stem and a bonnet. The T-shaped fitting has an inlet which is at its base. The T-shaped fitting also has an outlet which is at one of its arms. The stem projects through its other arm of the T-shaped fitting within the center of which the bonnet slidably supports the stem. The bonnet is sealed to the end of the T-shaped fitting by a ring gasket and is secured thereto. The bonnet has a pair of cylindrical bearings which support the stem. Within each of two annular grooves a neoprene o-ring is disposed between one of a pair of leather non-extrusion rings in order to form a pair of spaced sliding seals between the stem and the bonnet. The adjustable valve also includes a flow cone and a removable flow nozzle. The flow cone is mounted on the stem and cooperates with the removable flow nozzle which the T-shaped fitting threadedly supports within its outlet.
U.S. Pat. No. 4,132,386, entitled Valve Mechanism for a Control Valve, issued to Eugene O. Lee on Oct. 2, 1979, teaches an adjustable valve which includes a T-shaped fitting, a stem and a bonnet. The T-shaped fitting has a first bore extending therethrough and a second bore adjacent and perpendicular to the first bore. The stem has a first end and a second end and extends through a first end of the first bore. The bonnet forms a seal between the first bore and the stem. The adjustable valve also includes a valve mechanism for controlling the flow through the adjustable valve. The valve mechanism includes a flow nozzle and a flow cone. The flow nozzle has a bore which is axially aligned with the first bore of the T-shaped fitting and is disposed within the first bore adjacent to its second the end. The flow nozzle has a cylindrical inner sidewall and a truncated-conical outer sidewall adjacent to its top portion and a cylindrical outer sidewall adjacent to its bottom portion. The flow cone slidably engages around the outer cylindrical sidewall of the seat and is mechanically coupled to the stem so that its inner sidewall may travel along and adjacent to the outer sidewall of the flow nozzle. The flow travels between the truncated-conical outer sidewall of the flow nozzle and the inner sidewall of the flow cone so that it may impinge upon itself.
U.S. Pat. No. 4,679,592, entitled Valve Seat Design to Reduce Cavitation, issued to Paul C. Lamb on Jul. 14, 1987, teaches an adjustable valve which includes a valve body and a valve mechanism. The valve body has a chamber with an inlet passage and an outlet passage. The valve mechanism includes a flow cone and a flow nozzle which form a trim to reduce cavitation. The flow nozzle has a bore and is disposed in the chamber of the valve body between the inlet and outlet passages. An end portion on the flow nozzle closes the bore. A truncated conical surface on the flow nozzle has a plurality of orifices extending therethrough and communicating with the bore. The flow cone has a skirt portion and a pocket which has a truncated conical wall. The valve mechanism movably secures the flow cone in the chamber of the valve body such that a portion of the flow nozzle extends into the pocket in the flow cone and the skirt portion of the flow cone covers a portion of the plurality of orifices in order to form a plurality of tortuous flow paths. The flow cone and the flow nozzle are axially movable and have frustoconical facing surfaces which form an annulus therebetween to control flow. The flow nozzle has an external frustoconical surface and a plurality of pairs of ports communicating with an internal bore. The ports are aligned so that flow from each port impinges upon another within the chamber of the flow nozzle to reduce cavitation.
U.S. Pat. No. 2,782,800 and U.S. Pat. No. 2,927,767 teach adjustable valves which have flow cones which are conically shaped and which are to be inserted into a flow nozzle. The interface between the surface of the flow cone and the surface of the flow nozzle serves not only to control the flow through the adjustable valve itself, but also serves as the shutoff when the adjustable valve is closed. This interface is therefore subject to wear by erosion.